Unfortunately there is a long history on this forum of problems when using the Tamron 90mm with Remote, going back at least 9 years. I have the f004 version which has always worked for me with the D610 and D750, although someone said that the f017 version also worked for him. If you do a search for ...

Catherine, I think making older versions easily available wouldn't clutter up the download page as just one link is required and could make life easier. Another photo software I use has this link under their curent version:
"Older Downloads (click to view)"

Hope the foll. helps:
The last D750 firmware update in 2021 was C: Ver 1.1.5.
When you turn "Network Communication" to "on" your device should see "Nikon WU2_ ...." to connect to.
Sometimes I have to "Reset" in "Network Settings" for this to happen.
The D750 won't remember the settings once switched ...

It turns out that the problem with Remote v3.9.11 is that it is not compatible with Android 13. I tried on my old discarded Galaxy tablet running Android 6.0.1 and everything worked fine. So there's a possible solution. C'est la vie.

Thank you, I have sent a bug report.

Catherine, I tried that version (3.9.11) after uninstalling the 4.3.1 version but it would not connect to the camera no matter what I tried.
Then I updated to 4.3.1 and it connected straight away.
Is there a technical problem with getting the Nikon Video Recording to work again on the latest version?

Catherine, it is a D750. i know this will not allow recording video over WiFi commands but I am using it tethered to Android.
Your Play Store download page does state "Issues with Nikon cameras fixed, but video recording with Nikon is temporarily impossible".

I was trying to use Remote to record video. It worked fine on Windows but not with Android. Now I have discovered a note for the app 4.3.1 download "Issues with Nikon cameras fixed, but video recording with Nikon is temporarily impossible".
Is there any plan to fix this issue please as it used to ...

A word of warning when buying OTG cables.
I bought a cheap cable for my new Samsung phone and Remote was very jerky. I then bought a more expensive UGreen cable and all works perfectly now. Not sure what the difference between them is though.

If you go to "help" in the program/app you will get the complete instructions. They are very comprehensive. As has been pointed out by wake689 the auto focus can be used to set the first near or far points but then the chevrons are used to set the end focus point manually. The steps will be ...

If you read the Helicon instructions they say you have to use an "on the go" OTG cable for Android and not all Androids support that but most do

Yes the Tube sits behind the lens and controls it, not the camera, so you will need a lens with built in motor. Helicon Remote will work in this case though.

If the lens is manual focus only then there can be no way for any software or hardware to adjust it in camera. But you could use a focus rail with a stepper motor (eg stackshot or Wemacro rail) controlled by Helicon Remote.

Have you done the essential calibration first?

To me Helicon Focus is very straightforward to use and does the job well so I haven't bothered trying Zerene.