DnD 5th encounter building

[Lady Quixote]

Hi there,

I'm looking for help tuning some encounters for a one shot DnD 5th edition game.  I've played a few games oneshot games (with level 1 characters) but want to test out things at a slightly higher level.  I created an adventure for level 4 characters but as it's my first time creating for 5th edition I'm not sure how balanced my encounters are.

Have anyone created encounters for level 4 characters and could look over my encounters and give me pointers?

Thank you for your time and help
Matt