How to make a chandelier for my new gazebo using old utility lamps?

Are you asking how? It looks like metal. Could you drill or poke holes into a design on both pendants so the light sparkles through? I love that look at night especially for an outdoor lamp. Then when you hang them, maybe hang one a little longer than the other and put it in the middle of your gazebo. If it is a covered gazebo, just make sure you unplug it after every use when it is outside. I repurposed a birdcage into an outdoor lantern by just using a lamp kit. Since it is under a gazebo and doesn't get really wet I used a lighting kit for indoors but we unplug it being outside when not in use. I thought you might like to see it under the gazebo all lit up. https://karupp-did.net/birdcage-re-purposed/

I love the lights at night under a gazebo. Good luck!

You can also drill holes along the bottom and add crystals.

Two person job when hanging. FIGURE OUT where you want your light to go. CUT a large round (or whatever shape you want) piece of cardboard & cut a center hole for your light cord. Paint & decorate the cardboard piece either with paint only, stucco, gems, glass pieces or any decorative medium you want. Paint your light fixture & let it dry (if desired) & the cord matching the paint in the gazebo. Get your cardboard piece & attach one half. Let your second person hold the cardboard piece up while you insert the light cord thru the hole & TAPE down the backside. Finish attaching the whole thing. Tack down the cord running to the plug. Painting the cord will make this blend into the paint job of the gazebo & less noticeable. You're done.

Dollar store has wire baskets, cut a hole in the bottom and slide over the cord. You could keep the metal shade that you have or remove it and add bling to the wire baskets, crystals, beads, pearls, fringe. What ever you can imagine.

Scavenge old sparkly jewelry from thrift stores and garage sales. Take it apart if you need to to make long strands. If you need to restring stuff, use waxed dental floss - it's strong and should be relatively weather proof.

Using binder clips (maybe spray paint them first to match the light cover), attach strands of beads to the bottom of the lamps (you can squeeze the sides of one of the little wings on a binder clip and the wire thing will pop out - run the bead strands through that and then reattach it to the clip by squeezing and sticking the ends back into the holes in the binder clip side). Make the strands different lengths so you will have multiple levels of sort of swooping strings of beads. Just clip the clips onto the exiting fixture at even intervals and you're done.