..., though it's still no clear to me what i should start doing. If someone guides me how to start, i will help as i can.
Have you gone through the sticky topics here :
http://www.magiclantern.fm/forum/index.php?board=25.0Including
http://www.magiclantern.fm/forum/index.php?topic=9517.0Try, Fail, do it again.
Take breaks.
Take pictures on your breaks.
Look for shortcuts, (I'm sure the innards are 98%+ the same as the 700D- only the buffer size may be slightly less on the 100D, and we have a combined Q/SET button- maybe cross reference with people working on the existing EOS M ports?).
Persevere.
Dont rush
Start Forum threads.
Ask for help.
Give help where you can.
Dont be afraid to get it wrong, post your mistakes, maybe you will find a general ML bug along the way , when you think it your fault. Then you will be helping the whole community!
Most of all
do not be afraid to ask questions! People who contributed/maintain the other ports once knew about as much as ML Dev. as you do now.
Yes I would love to donate to the whole ML (and I will eventually! ), but I also would like to give a little something to the people making this specific SL1 port happen. At worst you(and whoever else you team up with) will maybe get some coffee money for your efforts, at most you maybe could get a 5DMK3 from all the donations you receive, maybe? :p
Well maybe, I don't want to tempt you with money, that is wrong, you should only really do it because you want to- just like a lot of the great people here have done so with the other ports.
Good Luck, Should you wish to accept this challenge, the force shall be with you and whoever you take with you!