Macro-algae help

[Kapachuka3]

I’m looking into getting some macro algae. I however happen to know next to nothing about it. i just think it would look cool. I have 3 conchs, 1 urchin and some coral. What would be some cool species to keep, how do I acclimate and where would I put it? Does it come in frags, would I put it on top of rocks or something?

 

[Kapachuka3]

Also, does anybody know may types that are easy to care for that look like grass and grow in sand beds?