Before deepening into the Zone, it's necessary to traverse the old railroad embankment. The only safe passage is guarded by the militaries. However there's a small tunnel to the left, rookies usually go through it. There you'll be awaited by one of my debtors.
― Sidorovich
Meet the Journeyman
Pretty straightforward, just yomp up from the Rookie Village to the Bus stop and the Mill, picking up anything that you may have stashed there in the interim. Move towards the embankment using the Mill buildings as cover and head for the location of the Journeyman on the minimap, avoiding any anomalies.
Since the Journeyman is dead you may have to chase off a few Blind dogs before approaching his body. Searching his remains concludes the mission and provides the Traverse the Railroad Embankment mission.
Traverse the Railroad Embankment
There are a number of options for completing this task:
Journeyman's PDA
If you read the Journeyman's PDA, it states that the anomaly is moving, and there is a possibility to time it's movements from one end to the other. However, the anomaly moves from the south end of the tunnel to the north end, so it's a one-way passage.
By watching the clusters of electrical bolts, you can tell when to move forward. If you set the anomaly off, just step back a little until the cluster either fades away or moves forward.
Use Bolts
What Sidorovich doesn't tell you is that Rookies that use the Underpass, wearing Leather jackets or Bandit jackets or even Merc Suits, quickly end up dead no matter how good they are at using their Bolts to discharge the Electro Anomaly cluster preparatory to running through.
Yes, there's a nice safe area in the middle of the Underpass where you can 'patch up' before running the other half of the anomalies, but unless you have a serious suit on or three Battery artifacts on your belt, it's a sucker bet.
Go Around
It's much easier to run back through the Mill, over the road and through the embankment fence on the other side of the Railway bridge.
Military
Another approach is to either pay or fight the Military at the Bridge, which is also pretty suicidal at this stage of the Game since you won't have a PSO-1 scoped rifle, may only have a Mail jacket or a Merc Suit and your best pistol is likely a Fort-12 or a PB1s. However, if you want to try it, the loot is well worth the effort. One strategy is to climb up the southern embankment, use the cement retaining wall as cover, and go for the head-shot.
Alternatively, just 'run the embankment' without mixing it, get clear into the Northern part of Cordon concluding the mission. At this point Sidorovich talks to you and you get the "Meet Fox" message at Fox's camp and the Learn something about Strelok from Fox continuation mission. Make sure you have a Medkit handy.
Notes
See also the Cordon/Walkthrough and the Underpass links for more tips (especially tunnel walking).