Lynn,
to be homest, it may be easier to buy another one.
There are 3 ways to propogate Ti.
One is to cut the plant off with a good stretch of "usable" stem. (stem without leaves, where the leaves have shed naturally prior to cutting). You can place the bottom of the stem in water and try to root it that way, like any cutting. The stem that you leave behind, attached to roots, will eventually resprout a new stem and grow leaves.

Or, you can cut the stem into pieces, 2-3 inches long, lay flat in a dish of soil, keep moist but not soggy, and wait for new plants to sprout

Or, you can unpot the plant, wash all the soil off the roots, and see if it has any white "root nodes". If it does you can cut those off and plant them, and sometimes they will grow a new plant. Of course you then repot your old plant. It may set it back some.

Unless you just want to sacrifice your plant's growth, and possible lose your plant and your cuttings, this time of year is probably not the time to try to propagate this plant under your in-house conditions. You should probably wait til its reliably warm and sunny outdoors and do it outside.

That's just my opinion. I have never dealt with stuff like growlights and bottom heat for propagating anything, but I have propagated a lot of Ti.