An algorithm is simply a set of instructions.
When it comes to algorithmic trading computer programs are using these instructions to make trades at an extremely fast pace. They can do this much faster than a human is capable of doing. These days, algorithmic trading dominates the daily trading volume (mostly via big money hedge funds). This is something that will likely increase in the future. Most market makers are now using this process. Even retail traders are getting into the algo game. Down the road, the ability to create algos for trading via your broker software will be common place. An interesting question will be where can this go in the future. Imagine algorithmic trading combined with the ability of A.I. and machine learning. Technology is moving extremely fast and who knows where this could all lead.
Related to your trading:
Big money can be made catching low float breakouts on manipulated algo squeeze programs. Watch for support levels on big volume where it seems a whale may be buying up shares. Concerns with algorithmic trading are a hedgies ability to blow up low float stocks quickly via running these programs, so you must be careful on the short side of floats under about 20 million. There are many questions about whether or not this should be legal.