Why is reading important?
It helps build your vocabulary and improve your spelling.
How much reading should I do a day?
I would suggest at least 30 minutes a day if you can.
Here are some websites:
This website has readings on many topics.
There are easy options to more advanced options.
ESL - Reading (rong-chang.com)
What level should I choose?
If you have a lot of trouble with spelling, start with the easier readings first and do a few each day. You can choose something more difficult if you don't have many problems with spelling. Identify which words or phrases are challenging and look up the meaning using an English dictionary rather than a translator. I suggest you use this one.
This website has current news articles written in easier English and has a voice recording for each article.