Luckily, the maintenace of a fountain pen is fairly straight forward.
Clean your pen is with water.

After flushing some water across the nob of the pen, I stand a pen in a glass of regular water. The ink, being heavier than water, will flow out of the section. I find this one of the best ways to clean your pen. Use room temperature water. Hot water could loosen sealed areas.
A fountain pens is an amazing creation, look after your pen
Your fountain pen is a complex creation and required good care.
First of all, how do you hold a fountain pen? It matters as proper grip and pressure protect the nib’s tines and keep ink flowing smoothly. Hold your pen lightly at a comfortable angle (about 40–55° to the paper). Rather than focusing on pressing down, let the nib glide across the paper. Use even pressure with the nib flat across the paper so that both tines of the nib get equal pressure. No need to press overly hard. Try not to twist the nib sideways.
Using the right inks and filling methods prevents corrosion, clogging, and unpleasant surprises when switching colors. Make sure you use inks that are specifically labeled “fountain pen” or water‑based fountain‑safe inks. Follow any instructions that come with your pen in terms of inserting ink cartridges or ink converters. If your pen fill with a piston, there most likely are notes or instructions such as which to turn a nob to expel ink out or draw ink into the pen. Don’t use India inks, calligraphy inks, or pigmented/carbon/resin inks made for dip pens—these can clog or damage feeds and are usually not removable. Never return leftover ink from a pen back into the original bottle.
The finish of the the pen is specific to the type of material. As a general rule use a soft cloth and water clean. Avoid cleaning fluids as it could damage the finish of the pen.
For sterling silver trim, clean the silver with a silver polishing cloth. If you have to use silver cleaner, put some on the cloth and then rub the cloth on the pen. Don't put silver cleaner on the pen itself. It can get into small places and be difficult to get off.
Lacquers are often though as being delicate surfaces, but they are quite durable. Use a moist soft cloth to clean the pen and avoid abrasive cleaners or chemicals.
Regular cleaning, the flush, is important. This removes old ink residues and prevents clogs, preserves color fidelity, and keeps the feed working. Most makers recommend flushing to clean out existing ink in the pen before switching inks. Periodically flushing is helpful if you are only using one ink in your pen.
For routine cleaning, remove the cartridge or converter and flush the section/nib with cool or lukewarm water until it runs clear. This usually takes 7 to 10 flushes. Also flush out the converter. Don’t use hot water as that could damage sealings or finishes. Stay away from harsh household chemicals.
Changing ink colours? Then do a clean so you see the real colour of the next ink.
You will have to do a deeper cleaning if there is dried or stubborn coloured ink. Yes there is a price to pay for some of the highly saturated intense coloured inks.
Soak the nib/section in room‑temperature or slightly tepid water for a few hours or overnight. You may add a drop of mild dish soap if the plain water clean does not work.
After difficult cleans, it will be a reminder to not leave pens filled with ink and not used.
Longer period of non-use - stand your pen vertically, nib up. This has the ink settle away from the nib.
Cap and lay your pen horizontally for quick access.
It is a good idea to give a fountain pen a good flush every couple of months. This means, pushing in and out the converter or piston while hold the nib of the pen under a stream of water. Then dry out the nib and ink mechanism with a towel. I have my pens stand in a glass with a rolled up paper towel in the bottom. The paper nicely pulls out water from the nib/feed.
I am always amazed at the trail of ink that flows from the nib as the pen sits in water. I thought it was clean, but the fine lines of ink flowing from the nib through the water says it was not.
If you have not used the pen for a while, and you go to write with it and no ink flows, don't just press harder and harder on nib to get the flow going. You may damage the nib. Make light short strokes. Use the same pressure as you would write. The strokes will activate the flow. If nothing happens, then dip the nib in some water.