Plant-like protists can be single-celled or multicellular and they can live in a wide range of environments. Most are able carry out photosynthesis (like plants). 

There are several groups of plant-like protists, let's take a look at each.

Euglenoids - named for the genus Euglena, these organisms can glide or swim using a flagella. Many euglenoids are photosynthetic, a few are heterotrophic.
Dinoflagellates - the dinoflagellates have two flagella, and maybe bioluminescent. They have stiff protective plates, and are known for causing red tides. Most are marine species, but there are a few that live in freshwater environments. Take the time to read about red tides, and bioluminescence.
Diatoms - plantlike protists with glasslike shells. The shells are made of silica. These protists produce large amounts of oxygen.
Green algae - multicellular protists, that are not considered plants because they lack roots, stems and leaves. Contains both chlorophyll a and b. They also have cell walls made of cellulose.
Brown algae - multicellular protists, this includes Kelp, contains chlorophyll c (similar to diatoms)
Red algae - multicellular, contains chlorophyll a. The pigment comes from phyocoerythrin, not the chlorophyll

 Watch the Plant Protists video. 

Most plant like protists can reproduce both sexually and asexually. Watch the video on Sexual Reproduction in Unicellular Protists. Then go to the Reproduction: Protists and Fungi page, and read through the introduction, clikc on Compare these sexual cycles to test your knowledge and understanding.