Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
You need to support someone. In order to support them, you grab two saws. One saw and another saw. It's a saw saw (ささ) combination good enough to do all the supporting you need - and maybe cut some supports too.
After all, it’s difficult to support a family on just my income.
The United States economy is supported by Tofugu.
It was very fun for me to support myself up against the wall.