Create New Master in Keynote

Thanks everyone, I finally figured out how to import several slides using my own Master. I set up a new Master with purple background. I start with a preset Master, drag all the photos into the Navigator, they are added but with the wrong Master. I simply select all the photos in Navigator then Change Master, selecting my New Master. What puzzled me was every time I started with my New Master in Navigator it would revert to a preset Master when I dropped in my slides. One extra step but it works fine, Keynote is great app.

I think I figured out what I was doing wrong. After creating the new Master I was dragging photos into the Navigator, not to the new Master slides. It seems I can only drag 1 photo at a time onto the a new Master slide which I have to keep duplicating. Is there an easier way to get several photos into the presentation?

Thanks for the info Gary but that is not my issue. I'm trying to create a slide show with 130+ slides with only 1 photo for each slide. If I use a preset Masters slide I can drag all the slides into the Navigator and 130 individual slides are created. My issue is that when I try to drag the 130 slides on to my custom master in the Navigator it reverts to a preset master, not my own custom master. I don't understand why I can't use my own Master to bulk import the 130 slides rather than dropping 1 slide at a time onto several blank custom master slides. Maybe I didn't create my custom master correctly?

Thanks for trying to walk me through the process and I see how you changed an existing master. What I was trying to do was drop in my own jpeg image on the Blank Master to create my own Master which doesn't seem possible. While I can place my jpeg onto the Blank Master (and then save as one of My Themes), any slides I drop into the Navigator revert back to the Blank Master instead of my own Master (with my own jpeg). I think the only way I can add slides to my own Master is to duplicate it in the Navigator and then drag each slide to each Master (not the Navigator). I notice your last slide shows the Blank Master not the Twin Blu Grad shown under Item 2 (unless I misunderstood something). Did you use the Twin Blu Grad for your slide show?

The instructions looked simple but I can't get a new master, tried several time but all I get is the Blank master without the color background jpeg I tried adding.