read some of the information in the clown/anemone section, it has a lot of information that will help you.
General guidelines are have your tank setup for 6+ months and stable prior to adding any nems. BTA (bubble tip anemone) are considered to be the easiest of the hosting anemone species to keep. Whether or not your clowns will associate with the anemone is dependant on the clowns, If you have false/true percs, BTAs are not their natural host.
As for feeding anemone, normally any meaty sea fairing food is acceptable, not to large of portions, and around every other week or once a week for feeding.