To make the blocks behave like annotative text, you need to go to the drawing explorer and select the "blocks" tab, then select the blocks you wish to make annotative nd then click in the "Annotative" column
Once this has been done, you can then select the block in the model space and then in the Properties bar under the "Misc" section there is an "Annotative scale"
If you want to use the right click shortcut menu's in BricsCAD, make sure in the options the are set up like the image below. Just type in Shortcut at the top and it will take you to this position
You can then add more than one scale to the list if you want , depending on how many different viewport scales you have and what you want to see in each of them. The block will now show up in the correct viewport with the scale needed for the right annotative scale.