英和和英

to link

to link

the missing link

Click the button

to press a button

push the button down

to attach a stamp

to affix one's seal to a paper―seal a bond

to affix a tally-impression over two folds of paper

to finger a button―fumble a button

the stroke of a key

the act of affixing a seal at the joining of two papers

connect or link

press a button

to undo a button―（上衣のボタンなら）―unbutton one's coat

to undo a button―unbutton one's coat

to make a thumb-print （on a document）―seal a document with a thumb-print

fasten buttons

provide with buttons

to fasten one's coat with buttons―button one's coat

to sew a button on

engage the clutch

sew the button down

The below link will direct you to a third-party site.

turn a knob

looping the loop

loop the loop

disengage the clutch

tie the knot

undo the ties of