Lots of lectures on linear algebra are available. I can recommend those in the YouTube Channel 3Blue1Brown: they're very short and all the topics are useful in the context of our course. The MIT Lectures of Gilbert Strang are also good, but more ambitious, and we won't get to all the topics he discusses. (Virtually the entire MIT course is available at the link.)
There are mathematics Stack Exchange tags: linear algebra and matrices.
Most computational problems in linear algebra can be solved by a variety of computer algebra systems. There are even calculators in the form of web pages to do this.