Formally arrest and caution him immediately upon handcuffing him, if possible (or as soon as is practicable), but only explain the detailed reason(s) for lawful arrest after he is safely in custody; in any case, do not hold a trial on the street.
If the arrestee is totally under control, make a note of his Charter/Miranda warning and the time it was made (as well as who else was present).
PRO TIP: officers can use a lettered code to save writing time when reciting or reading mandatory cautions from cards to arrestees (i.e., Arrest, Read Rights, and Warned = ARR&W).
Identify who he is, his address, and what scars, marks, tattoos he has to ensure his later identification in court (take a picture!).
Apply a spit mask/”bag”, and/or hobble him if needed (or tie his shoelaces together to keep him from kicking).
It would be good practice to make a physical note that the handcuffs were checked for tightness and double locked (CFT+DL).