hi there and welcome to the world of fishkeeping
i appreciated you've asked about fish specifically so i'll try and keep most of my reply on topic with that.
however as an absolute beginner there is one thing you need to learn about before you add fish, it's the nitrogen cycle and it's basically how your filter keeps your tank healthy. have a read of
this topic which should explain more.
now onto the fish, a 35l tank is roughly 10 us gallons, there's a basic guideline for stocking which is 1" of fish per us gallon of water. you work this out on the adult size of the fish, so for a 10g tank you can have 10 fish that get to 1" each, or 5 2" fish, mix and match to get roughly the right numbers.
in a tank that size you don't want any fish that will get bigger than 2/3" really, now bear in mind fish sold in shops are usually young so don't assume they are at adult size, more often than not they will grow and you need to take this into account.
can you give us some details of what you want for this tank, peaceful calm fish or lively ones, lots of fish or just a few nice specimin's, fish with pesonality or one's that are beautiful? there are so many choices without narrowing it down it can be very difficult to advise.
