select cannot open the constraints ribbon

[Anonymous]

select cannot open the constraints ribbon

[MoshiurRashid]

Would you please add a picture so that we can understand what you are looking for?  

[steven-g]

LT cannot create constraints if that is what you are trying to do? only view or delete them from the 'parameters' tab of the ribbon.

[pendean]

Not a feature of the lower cost LT version of AutoCAD: if you need that ability you will all the time then need subscribe to full AutoCAD https://www.autodesk.com/buy-online