Will I be able to claim my PE outfits and computer as expenses since I used them to post videos?

If you are a W-2 employee, you can't deduct any work-related expenses.

If you are self-employed/independent contractor and filing schedule C, you can deduct expenses that are ordinary and necessary for making money.  However, there are special rules for clothing, computers and cars.

You can deduct certain car expenses as described in publication 463. https://www.irs.gov/pub/irs-pdf/p463.pdf

It's hard to explain in more detail without knowing your specific vehicle use.

A computer is "listed" equipment.  You can take a deduction for depreciation (wear and tear) by listing is as a business asset, but you must allocate your expenses to the percentage of business use, and you must have some kind of records to support your business percentage, if audited. 

Clothing can't be deducted as a work expense unless it is unusual and distinctive so that it can't be worn for personal use.  For example, a priest can deduct his collar but not his black shirt.