nice game, sometimes can't move units into hex with other units in it

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I just bought this game and am doing the tutorial mission at Omaha and Point de hoc.
The game looks realistic and fun with nice looking map and good manual (I read 1/3 so still need to finish it).

I am carefully reading the manual and tutorial info panels.
My problem is when I move a unit into a hex that already has some of my units in it and it never allows the move. And yes there are only a few units so under the 9 unit limit.
Right now I am trying to move an artillery and engineer from the boats to Normandy into a hex with my units in it. When I click on the artillery, then left click onto the land hex to move there, the game switches unit selected to a friendly infantry in the target hex. I tried over & over & over but am never allowed to move the artillery there despite full movement.
So I gave up and tried to move the artillery inland past the shore hex and I finally was allowed to move the artillery because the target hex had no friendly units it. Then when I clicked back on the boat hex to get the engineer, the artillery CAME BACK to the boats and used up all its movement doing that silly yo-yo move.
So why can't I just move the artillery onto the shore hex to be with my other units there? This problem is happening to me everywhere. This is just the latest example. I keep having to give up on moving units into hexes with friendlies in it because I am not allowed to because the game switches selection every time to a unit already in the target hex.

Is there a hotkey to help the move happen without switching selection? I tried shift left click but it still does the switch and refuses the move.

Here is a picture of it after the engineer moved down to the yellow border hex. The artillery is still offshore now without movement points due to the yo-yo move. The shore hex below is where I was not allowed to move it.

https://imgur.com/Jr4hrY7

[GiveWarAchance]

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[GiveWarAchance]

Sorry again another problem

I tried to bombard a German position on the coast with my artillery, but the artillery moved onto the German hex. I tried to move infantry onto the hex but they will attack normally (which I want to do).

Why did my artillery move onto the German hex instead of doing a bombard? You can see the artillery sitting on the German hex on to the top right area on the coast....

https://imgur.com/cPsEj2o

Edit: I came back to this game later and used U to undo the move and then was able to bombard with the arty. I wonder why sometimes artillery want to move onto the German hexes instead of fire. I don't see a bombard button so I can only hope for the small explosion icon to show over the target hex instead of a yellow arrow moving there.