I have the above mentioned lens, but no instruction manual. Could you please explain how to use the macro option? is there a switch to macro? or what to do?
Thanks

Usually there is a locking ring on the F-stop ring. There should be a button. If there is not have you tried it in macro mode - shooting extremely close ?

you can aslo try here for a manual on your lens.

https://www.tamron.com/support/instruction.html