Download the installer from the link you were provided.
Once completed, open downloaded file and start the Syncro installer.
Select Install for all users of this computer and click Continue
Click Install button
On the Provide Permissions dialogue, Enable both Full Disk Access and Screen recording. Do not click Continue yet.
Open System Settings and select Privacy & Security. Select Full Disk Access on the right. Find SyncroMSP in the list and click on the toggle
The Provide Syncro Permissions dialogue box should change to Allowed!
Go back to Privacy & Security and select Screen Sharing on the right. Find Syncro MSP and click the toggle switch. The Provide Permissions dialogue box should change to Allowed!
Click continue on the Provide Permissions dialogue box.
Once that has completed, find the Splashtop icon in the top right banner bar. Click on it (right click?) and select Preferences.
Click on the red ! in the top right corner.
Open System Settings -> Security & Privacy and allow the permissions listed in the dialogue box for the app Splashtop Streamer.
Accessibility access:
Full Disk Access
Microphone access:
Click Ok to allow Microphone access.
Screen Recording access:
After allowing Screen Recording, Quit & Reopen Spashtop Streamer.
When completed, there should be green check marks.
Click Finish and restart the computer.