>>Guide, I am sending a man to meet you, we have important information for Doctor, help him out.
>>Guide: 'Good. But, Ghost, let's not repeat what happened last time. You make the trip yourself, I've wanted to have a chat with you for a while. I'll be waiting at the usual place, in the camp by the bridge. Don't get lost and don't let the army patrols get you.'
― Ghost: Entry #257
Meet with Guide is a primary mission segment in Shadow of Chernobyl.
Acquiring the Mission[]
Near the completion of the Find the documents in X16 lab mission, when you Find out what happened to Ghost, you receive the Meet with Guide mission.
Overview[]
Ghost's PDA offers a clue about meeting someone called Guide at the "camp by the bridge." Which is the same place you met Fox in the Cordon.
Mission: Meet with Guide[]
Coming out of Lab X-16, you have the second part of Find the documents in X16 lab on your PDA: Bring the documents to Barkeep and Meet with Guide. You have to pass Barkeep on your way to the Cordon. Following your PDA, you can see that Guide is in the same place where you met Fox. In fact, don't be surprised if Fox's corpse is nearby (and be sure to loot it for a possible stash).
When you talk to Guide, he tells you to meet Doctor in Strelok's hiding spot, which you discovered during the Find the Secret Stash mission. When the conversation is over, your PDA updates to show Meet with Doctor.