I need a little help with a ruger P95DC

Have my dads P95 that was missing the sear, sear pins and spring. I do not have much experience reassembling a pistol like this when it comes to details. I have purchased the necessary parts, I just need a little help getting it in place. Excuse my ignorance. Id like to do it myself rather than pay a gunsmith. Thanks ahead of time.

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Always do it yourself.