[How to add curves without getting cutouts]

Oh great! Thank you both so much, this helped a lot!

[How to add curves without getting cutouts]

Hey everyone! Just trying to figure out how to add curves together in a way that it still looks like the first picture. Is there a way to do this? Every time I try to combine the shapes, I end up with the second picture. Is it because the lines were drawn with the brush tool? Sorry if this is a silly question, I'm still learning 

Thanks!!

[Letters "filling in" when adding as curves]

Oh that's exactly what I needed! Thank you so much!

[Letters "filling in" when adding as curves]

Hello everyone!

I am a beginner still learning the ropes of affinity designer and I have a question about some of my letters "filling in" when I try to add them together. I am converting them to curves first and then use the "add" tool in order to make into a cut file for a silhouette or cricut machine. Most of the time it works, but some fonts and letters will fill in the inside of an O, E, or G for example. I have attached screen shots of what I am talking about. Please let me know if there is another way I should be doing this or a way to fix the letters!! Thank you so much!