Firestick devices really lack storage so here are some great applications we can use to free up space
(APPs at the bottom of the page)
Steps to confirm your Free Space
1. From the Main Menu scroll to hover over Settings.

2. Click My Fire TV.

3. Choose About

4. Check your free space

Install the APKs from the link below
Software Needed
Dangbei Assistant
MiXplorer
SD Maid