Is there a way to install onto a device not using the cloud

Is there a way to install onto a device not using the cloud ?
Ive got ssh access into root on the device using putty, i want to add a few more containerised apps to my device . or can i some how add my clould edtails to the config.jason aswell as the current details of the other user to be able to use the cloud to install as usual. i need to do it this way as the device manufacturer is using only a small part of the pi4 for thier uses i want to add further functions myself without deleating or effecting thier apps . I know its possible to do this as anouther company has added their own apps . i just dont know quite how ?

Hello @oly99 and welcome to the balena community @Atreus

Did you try to use the offline updates Offline updates - Balena Documentation ?

Let us know if this works for you!