I've done it with a floor jack, though a small hydraulic "bottle" jack would do. First loosen the mount nuts - bottom and top. Then I jacked against a scrap of wood placed under the front of the oil pan just enough to support the engine - take the load off the motor mounts To save yourself some trouble, I undid the 3 bolts holding the bracket to the block - this way you don't have to elevate the engine to get it above the top stud on the mount. Remove old mounts from brackets and replace, rebolt bracket, lower engine and tighten nuts.

For the rear, a floor jack under the rear of the trans, again with enough support to take the load off the mount and support. Depending on access to the bracket bolted to the transmission, you may have to remove the support first. The difficult part is restarting the 4 bolts holding the support to the body. May require some jostling of the trans, and or lowering and raising the trans small amounts to be able to get the bolts to start. Careful not to let the trans slip off the floor jack when jostling.

Remove nuts from both top and bottom of motor mounts on both sides.

Raise engine very slightly with a floor jack under the pan -- I recommend a piece of 2x4 or similar between the jack and the pan. Lift as little as possible so you don't strain the radiator connections, exhaust, throttle linkage, etc. Just get the weight off the mounts.

Unbolt the mount "ears" from the block, lift out old mounts, drop in new mounts, bolt ears back on.

Lower engine, tighten nuts on the new mounts top and bottom.