搭 (dā) is a verb meaning 'to put up,' 'to build,' or 'to hang over.' It often describes assembling temporary structures, as in 搭帐篷 (to pitch a tent). It can also mean 'to take' a form of transport, as in 搭车 (to catch a ride).
他们在草地上搭了一个帐篷。
tāmen zài cǎodì shàng dā le yī gè zhàngpéng.
They set up a tent on the grass.
我每天搭地铁去上班。
wǒ měitiān dā dìtiě qù shàngbān.
I take the subway to work every day.
工人们正在搭一个临时的舞台。
gōngrénmen zhèngzài dā yī gè línshí de wǔtái.
The workers are building a temporary stage.