I tried 2 PCs and 2 different browsers, and none seemed to work. I finally broke down & looked at the source code for the page, (something I swore I would never do after retirement.) Couldn't see anything obvious, so then I just tried plugging the addresses for the unaccessible topics from the source. They all worked fine, so here are links.
A beginner's guide
https://www.quiltingboard.com/resources/article-60.html
Applique tips
https://www.quiltingboard.com/resources/article-14.html
perfect Quarter inch seam
https://www.quiltingboard.com/resour...ticle-116.html
Pin cushion 1
https://www.quiltingboard.com/resour...ticle-125.html
Pin cushion 2
https://www.quiltingboard.com/resour...ticle-126.html