If you have never worn a pair before they will feel a little odd when you first put them on. Remember they are not designed to fit like a shoe. You don’t go shopping for a helmet and expect it to fit like a hat! Those boots have a very specific job to do and have been designed by professionals with years of research and development. They will probably feel tight, some-what restrictive and not super easy to walk-in.

Boots are tight for a reason. Designed to protect your ankle joint from damage, the boots need to encase your leg like a cast.

Boots are hard to walk in for a reason. Humans walk with, among other things, flexion and extension of the ankle. Extreme movements (hyperflexion and hyperextension) in either of these directions can be very damaging to the ankle and even micro tears in the joint ligaments can be very painful and take weeks to repair. Boots protect you from this kind of damage by limiting the range of movement available to your ankle joint. This can make boots hard to walk in. But remember, once on the bike, you’re not walking anywhere! Most new riders will get used to the feeling of boots in 1 decent ride. Some may take a little longer. All will agree though that they become something you cannot ride without.
High-end models make use of clever hinge systems to protect the ankle from these sorts of hyper-flexion and hyper-extension injuries while still allowing enough movement for easier walking and gear-changes, and rear brake control.