Imposing tariffs, and starting a trade war, will surely mean that imports will shoot up in price for the consumer. Exports will suffer, which is likely why he'll also try to devalue the dollar - to make exports be more attractive amid the receiving countries tariffs.
So that's a double-whammy as far as prices go, for the consumer.
His grand plan is of course to bring back manufacturing to the US - or that foreign companies will set up plants in the US. But that doesn't happen overnight, and there's no automatic mechanism that will make the companies do so.
And Trump has been clear about imposing the highest tariffs on all Chinese imports. Now look around you, and try to estimate how many things you see that are made in China.
Then you have the other countries, too, which will get hit with tariffs.
That said, I have been contending that people experience prices and talking about lowering inflation when prices have recently gone up is net negative for the incumbent administration.