If you want to learn video editing and you don't have any prior experience in this field, you can follow the following steps:
Research on the internet which editing software is good in the market.
Choose one based on the learning content available on Youtube.
Watch all learning videos available on Youtube and try to learn from them.
Approach someone professional in the field and ask for an internship (paid or unpaid)
Do an internship there and work hard, and be observant.