Is there some restrictions with this two cards or something I'm doing wrong?
In fact, that combination doesn't have any restrictions, but notice that, at the moment you summon Chimeratech Overdragon (aka CO), all cards you control (including Future Fusion) are send to the GY, destroying CO.
To prevent this, you can protect Future Fusion, like having a Cyber Phoenix in the field.
And note that, CO can attack X (X = number of banned monsters) times only to monsters or 1 time directly, not both.
I play a Cyber Dragon deck too, and, it has some combos well taken like summon Cyber Dragon Infinity in one turn, but also some useless in the consistence of summoning any Fusion monster with ?Atk/?Def with Fusion Bond (gives you a monster with 0 ATK /0 DEF)
Also, it's a good idea to have Jizukiru, The Star Destruction Kaiju to ride off some annoying monsters in the field and summon Chimeratech Fortress Dragon.
For the tricky mecanics, you can read the rulings off each card and their interactions with the same archetype and nearest/closest cards, or try with and emulator like YGO Pro.
Since he destroys all other cards on your field it would destroy future fusion thus destroying him, but, with my deck I don't use future fusion as my main fusion card for getting overtech. i use future fusion as just a means to get every machine type in my graveyard, then I use overload fusion (which can fuse with creatures from the graveyard) to get him out using every material in my deck, it's just a simple one two punch, you use future then overload simple as that with just those two cards in your hand you can get a turn 1 14,000 chimera overtech dragon