Research is key noles! Definetly without a doubt I would only recommend a BTA, Bubble tip anemone, or Entacmaea quadricolor.
reasons are:
1) you are new this!
2) BTAs are the most successful anemone in an aquarium.
3) with the setup you have, your choices are limited.
Clownfish I would recommend,
Cinnamon (A. melanopus)
Clark (A. clarkii)
Tomato (A. frenatus)
Maroon (P. biaculeatus)
Red Sea (A. bicinctus)
Percs dont like BTAs and rarely go into saddle carpets, they do like Stichodactyla gigantea but I doubt you have one of those.
I have been keeping anemones for 12 years, one thing I learned is, to dedicate a seperate anemone tank. I have a 24x18x18 tank, with 3 BTAs and 5 bicinctus, red sea blenny, a few shoots of Kenya soft branching corals and some blue zooanthids.
Theres no skimmer on this tank, just alot of circulation and 150w HQI/65w PC. Change 10% water every 2-3 weeks.
One other bit of advice, BTAs will wonder around the tank alot till they find a cozy spot, so watch out for intakes on your pumps, they can get sucked up!