As rjcorraya-san already answered, ～してみる means to do something as a trial.　～してみた is the past form of it. ex, 歌ってみた、　踊ってみた、　食べてみた、買ってみた、etc.

弾く (ひく) is the verb meaning "to play" (a musical instrument). Almost all the time the Japanese people writes/types 弾いてみた at the end of the title of a cover song. It means "I tried playing it". For example, suppose you are watching this video： https://www.youtube.com/watch?v=5qyMbJnNtfE It says in the title, "I tried playing SAKURA by Ikimono Gakari on the Acoustic Guitar"... Hope my answer helped! Let me know if you want to know more about it. For example, the usage of ～みる. BTW, I hope that you already know the difference between the suffix ~みる and with 見る. Enjoy learning Japanese! (=^・^=)