Hi @newmannsalva. The machine has 100 needles. There are several youTube videos on how to increase, and decrease stitches. The machine has different positions for working and non-working needles. This 46 second short video illustrates increasing.
This video illustrates decreasing.

The tension is handled by the carriage. As long as you have plenty of yarn loose, then the carriage moves freely.

I can easily knit a blanket in an evening. I did my knit sample from this post in a matter of minutes. I have seen some people complaining about this machine, but so far it is working for me.